Well, Locus Map doesn’t seem to have different waypoint types.
That makes things easier.
According to their (very good) docomentation they have two rerouting options.
- Point priority - Locus recalculates the route to the nearest transit (or ‘via’) point on the planned route. If there are no ‘via’ points, it recalculates the route to the final point.
- Route priority - used when you deviate from the original line and want to get back to it - Locus navigates you to the original line as soon as possible and on the nearest place - the line (route) matters.
for more flexibility - Point priority
for more strictly following the route - Route priority
Probably because they don’t have @Tom to test their routing strategy to its limits 
Back to Kurviger
Currently we have:
Additionally:
viaPoints - mandatory
shaping points - may be skipped
The rerouting options:
- “Nearest waypoint” - the idea is flexibility, right?
- “Next unvisited waypoint” - the idea is strictly follow the waypoints in sequence - right?
- “Nearest point on route” - the idea is what?
My personal preference would be Nearest waypoint which gives the flexibility to automatically skip waypoints. But this is in some ways in contradiction to the concept of viaPoints, which should be considered mandatory 
So I would remove it in favor of simplicity.
“Nearest point on route” is a nice option at start of navigation, but as a rerouting option it does have the tendency to route you backwards.